Abstract
ObjectiveRespiratory syncytial virus (RSV) is a common pathogen during infancy, with the potential to cause serious disease and mortality in high-risk groups. The objective of this study was to characterize trends of RSV and bronchiolitis hospitalizations in the first year in a population-based cohort and assess differences in trends according to risk status.MethodsUsing an observational retrospective cohort design, we examined a California population-based dataset of vital statistics linked to hospital discharge data for up to 1 year after birth from 1997–2011. Infants were categorized by medical condition and then by gestational age. Medical conditions of interest included chronic lung disease, certain congenital heart diseases, or others known to affect risk for developing severe bronchiolitis. The primary outcome was hospitalization due to RSV; secondary outcome was hospitalization for unspecified bronchiolitis (UB) not coded as RSV. Annual person-year rates were calculated for infants <12 months of age during January to December of each year.ResultsOf 7,298,401 infants born during the study period, 121,230 (1.7%) had a medical condition associated with risk; these infants experienced 6853 RSV and 6568 UB hospitalizations in the first year. In infants without medical conditions, 96,694 RSV and 69,886 UB hospitalizations occurred. All-cause infant hospitalizations declined over time from 12.2 to 9.3 per 100 person-years. RSV hospitalization rates for infants with medical conditions decreased from 7.6 to 3.4 per 100 person-years, with the largest relative decline in infants with chronic lung disease (12.0 to 5.0 per 100 person-years). For infants without medical conditions, RSV hospitalizations declined from 1.4 to 0.8 per 100 person-years, with greater decreases among preterm infants with earlier gestational age. UB hospitalization rates remained relatively stable across the study years, from 6.2 to 5.4 and 1.0 to 0.8 per 100 person-years for infants with and without medical conditions.ConclusionsVarious interventions may have contributed to observed decreases in RSV hospitalizations from 1998–2011, which were greater in high-risk populations recommended for RSV immunoprophylaxis and not observed with UB. Further efforts to promote evidence-based practice and optimal targeting of appropriate interventions will ensure continued improvement in care for vulnerable infants.
Highlights
Respiratory syncytial virus (RSV) is a leading cause of hospitalization and can result in serious morbidity and mortality in infants, infants born preterm or with a high-risk medical condition such as chronic lung disease (CLD) or congenital heart disease (CHD) [1,2,3,4]
Of 7,298,401 infants born during the study period, 121,230 (1.7%) had a medical condition associated with risk; these infants experienced 6853 RSV and 6568 unspecified bronchiolitis (UB) hospitalizations in the first year
UB hospitalization rates remained relatively stable across the study years, from 6.2 to 5.4 and 1.0 to 0.8 per 100 person-years for infants with and without medical conditions
Summary
Respiratory syncytial virus (RSV) is a leading cause of hospitalization and can result in serious morbidity and mortality in infants, infants born preterm or with a high-risk medical condition such as chronic lung disease (CLD) or congenital heart disease (CHD) [1,2,3,4]. There have been reports of reduced incidence of RSV and/or bronchiolitis hospitalization in recent years for infants overall and for infants with CLD and CHD [1, 8, 9] None of these studies have employed a cohort design in which the population is prospectively followed forward in time; instead, they have used estimated denominator populations based on national birth statistics. Due to this design limitation, no study has examined hospitalization rates among preterm infants because gestational age (GA) at birth was not available for hospitalized infants. RSV immunoprophylaxis of high-risk infants with palivizumab was increasingly utilized in the United States during the study period following its licensure in 1998
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
